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Panchagnula S, Kamer J, Candian A, Hrodmarsson HR, Linnartz H, Bouwman J, Tielens AGGM. Laser-induced fragmentation of coronene cations. Phys Chem Chem Phys 2024. [PMID: 38884178 DOI: 10.1039/d4cp01301h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/18/2024]
Abstract
Polycyclic aromatic hydrocarbons are an important component of the interstellar medium of galaxies and photochemistry plays a key role in the evolution of these species in space. Here, we explore the photofragmentation behaviour of the coronene cation (C24H12˙+) using time-of-flight mass spectrometry. The experiments show photodissociation fragmentation channels including the formation of bare carbon clusters (Cn˙+) and hydrocarbon chains (CnHx+). The mass spectrum of coronene is dominated by peaks from C11˙+ and C7H+. Density functional theory was used to calculate relative energies, potential dissociation pathways, and possible structures for relevant species. We identify 6-6 → 5-7 ring isomerisation as a key step in the formation of both the bare carbon clusters and the hydrocarbon chains observed in this study. We present the dissociation mechanism outlined here as a potential formation route for C60 and other astrochemically relevant species.
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Affiliation(s)
- Sanjana Panchagnula
- Laboratory for Astrophysics, Leiden Observatory, Leiden University, 2300 RA, Leiden, The Netherlands.
- Leiden Observatory, Leiden University, 2300 RA, Leiden, The Netherlands
| | - Jerry Kamer
- Laboratory for Astrophysics, Leiden Observatory, Leiden University, 2300 RA, Leiden, The Netherlands.
| | - Alessandra Candian
- Anton Pannekoek Institute for Astronomy, University of Amsterdam, Science Park 904, 1098 XH, Amsterdam, The Netherlands
| | - Helgi R Hrodmarsson
- Laboratory for Astrophysics, Leiden Observatory, Leiden University, 2300 RA, Leiden, The Netherlands.
| | - Harold Linnartz
- Laboratory for Astrophysics, Leiden Observatory, Leiden University, 2300 RA, Leiden, The Netherlands.
| | - Jordy Bouwman
- Laboratory for Astrophysics, Leiden Observatory, Leiden University, 2300 RA, Leiden, The Netherlands.
| | - Alexander G G M Tielens
- Leiden Observatory, Leiden University, 2300 RA, Leiden, The Netherlands
- Department of Astronomy, University of Maryland, College Park, MD 20742-2421, USA
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2
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Schleier D, Kamer J, Jiao A, Schneider GF, Linnartz H, Bouwman J. Photoprocessing of cationic triazacoronene: dissociation characteristics of polycyclic aromatic nitrogen heterocycles in interstellar environments. Phys Chem Chem Phys 2024; 26:15547-15558. [PMID: 38756091 DOI: 10.1039/d4cp01387e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/18/2024]
Abstract
Polycyclic aromatic nitrogen heterocycles (PANHs) are present in various astronomical environments where they are subjected to intense radiation. Their photodissociation pathways give crucial insights into the cycle of matter in the universe, yet so far only the dissociation characteristics of few PANHs have been investigated. Moreover, most experiments use single photon techniques that only reveal the initial dissociation step, and are thus unsuited to replicate astronomical environments and timescales. In this work, we use the Instrument for the Photodynamics of PAHs (i-PoP) at the Laboratory for Astrophysics to simulate the interstellar photodissociation of a model PANH, cationic triazacoronene (TAC˙+, C21H9N3). Comparing the observed fragments to similar PAHs such as the isoelectronic coronene can give mechanistic insight into PAH dissociation. For coronene the major photodissociation products were found to be C9H+, C10+, and C11+. In contrast, fragmentation in TAC˙+ is initiated by up to three HCN losses often in combination with H- or H2 losses. In the lower mass region, the fragments show similarities to comparable PAHs like coronene, but for TAC˙+ the inclusion of nitrogen atoms into the ionic fragments in the form of e.g. (di)cyanopolyynes is also observed. These nitrogen-containing species may be important tracers of regions in interstellar space where interstellar PANHs are being photodissociated.
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Affiliation(s)
- Domenik Schleier
- Laboratory for Astrophysics, Leiden Observatory, Leiden University, PO Box 9513, 2300 RA Leiden, The Netherlands
- Lehrstuhl Technische Thermodynamik, Fakultät für Maschinenbau, Universität Paderborn, Warburger Str. 100, 33098 Paderborn, Germany.
| | - Jerry Kamer
- Laboratory for Astrophysics, Leiden Observatory, Leiden University, PO Box 9513, 2300 RA Leiden, The Netherlands
| | - Andy Jiao
- Leiden Institute of Chemistry, Leiden University, PO Box 9502, 2300 RA Leiden, The Netherlands
| | - Grégory F Schneider
- Leiden Institute of Chemistry, Leiden University, PO Box 9502, 2300 RA Leiden, The Netherlands
| | - Harold Linnartz
- Laboratory for Astrophysics, Leiden Observatory, Leiden University, PO Box 9513, 2300 RA Leiden, The Netherlands
| | - Jordy Bouwman
- Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, CO 80303, USA.
- Department of Chemistry, University of Colorado, Boulder, CO 80309, USA
- Institute for Modeling Plasma, Atmospheres and Cosmic Dust (IMPACT), NASA/SSERVI, Boulder, CO 80309, USA
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3
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Désesquelles P, Domin D, Xu L, Van-Oanh NT. Competition between Loss of H 2 versus H+H in the Fragmentation of the Fluorene Cation. Chemphyschem 2024; 25:e202300241. [PMID: 37877430 DOI: 10.1002/cphc.202300241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Revised: 10/18/2023] [Accepted: 10/23/2023] [Indexed: 10/26/2023]
Abstract
The fluorene cation is a frequently studied molecule in the context of fragmentation experiments. This is because of its potential role in interstellar chemistry, notably as a precursor of PAH cages. In this paper, we analyze H, H+ , H2 andH 2 + ${{\rm{H}}_2^ + }$ losses from the fluorene cation using the SMF (Statistical Molecular Fragmentation) model. We calculate the probabilities of all the 534 possible fragmentation channels as a function of the excitation energy, up to the loss of three hydrogens. Four different types of hydrogen atom pairings (from the same carbon, from the same ring, from different rings and across-the-bay) have been tested in order to determine which types contribute to the actual production of hydrogen molecules. The simulated breakdown curves are in very good agreement with different experimental results when same ring pairing is taken into account. It was possible to deduce from the model the locations of the emitted H, H+ , H2 andH 2 + ${{\rm{H}}_2^ + }$ species.
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Affiliation(s)
- Pierre Désesquelles
- Université Paris-Saclay, CNRS, Laboratoire de Physique des Gaz et des Plasmas, 91405, Orsay, France
- Huazhong Univ. Sci. & Technol., Sch. Energy & Power Engn., Dept. Nucl. Engn. & Technol., Wuhan, 430074, Hubei, P. R. China
| | - Dominik Domin
- Université Paris-Saclay, CNRS, Institut de Chimie Physique UMR8000, 91405, Orsay, France
| | - Lejin Xu
- Huazhong Univ. Sci. & Technol., Sch. Energy & Power Engn., Dept. Nucl. Engn. & Technol., Wuhan, 430074, Hubei, P. R. China
| | - Nguyen-Thi Van-Oanh
- Université Paris-Saclay, CNRS, Institut de Chimie Physique UMR8000, 91405, Orsay, France
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4
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Marlton SJP, Buntine JT, Liu C, Watkins P, Jacovella U, Carrascosa E, Bull JN, Bieske EJ. Disentangling Electronic Spectra of Linear and Cyclic Hydrogenated Carbon Cluster Cations, C 2n+1H + ( n = 3–10). J Phys Chem A 2022; 126:6678-6685. [DOI: 10.1021/acs.jpca.2c05051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Samuel J. P. Marlton
- School of Chemistry, The University of Melbourne, 3010 Parkville, Victoria, Australia
| | - Jack T. Buntine
- School of Chemistry, The University of Melbourne, 3010 Parkville, Victoria, Australia
| | - Chang Liu
- School of Chemistry, The University of Melbourne, 3010 Parkville, Victoria, Australia
| | - Patrick Watkins
- School of Chemistry, The University of Melbourne, 3010 Parkville, Victoria, Australia
| | - Ugo Jacovella
- Université Paris-Saclay, CNRS, Institut des Sciences Moléculaires d’Orsay, 91405 Orsay, France
| | - Eduardo Carrascosa
- Bruker Daltonics GmbH & Co. KG, Fahrenheitstrasse 4, 28359 Bremen, Germany
| | - James N. Bull
- School of Chemistry, University of East Anglia, Norwich Research Park, NR4 7TJ Norwich, U.K
| | - Evan J. Bieske
- School of Chemistry, The University of Melbourne, 3010 Parkville, Victoria, Australia
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5
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Buntine JT, Cotter MI, Jacovella U, Liu C, Watkins P, Carrascosa E, Bull JN, Weston L, Muller G, Scholz MS, Bieske EJ. Electronic spectra of positively charged carbon clusters-C 2n + (n = 6-14). J Chem Phys 2021; 155:214302. [PMID: 34879679 DOI: 10.1063/5.0070502] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Electronic spectra are measured for mass-selected C2n +(n = 6-14) clusters over the visible and near-infrared spectral range through resonance enhanced photodissociation of clusters tagged with N2 molecules in a cryogenic ion trap. The carbon cluster cations are generated through laser ablation of a graphite disk and can be selected according to their collision cross section with He buffer gas and their mass prior to being trapped and spectroscopically probed. The data suggest that the C2n +(n = 6-14) clusters have monocyclic structures with bicyclic structures becoming more prevalent for C22 + and larger clusters. The C2n + electronic spectra are dominated by an origin transition that shifts linearly to a longer wavelength with the number of carbon atoms and associated progressions involving excitation of ring deformation vibrational modes. Bands for C12 +, C16 +, C20 +, C24 +, and C28 + are relatively broad, possibly due to rapid non-radiative decay from the excited state, whereas bands for C14 +, C18 +, C22 +, and C26 + are narrower, consistent with slower non-radiative deactivation.
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Affiliation(s)
- Jack T Buntine
- School of Chemistry, The University of Melbourne, Victoria 3010, Australia
| | - Mariah I Cotter
- School of Chemistry, The University of Melbourne, Victoria 3010, Australia
| | - Ugo Jacovella
- School of Chemistry, The University of Melbourne, Victoria 3010, Australia
| | - Chang Liu
- School of Chemistry, The University of Melbourne, Victoria 3010, Australia
| | - Patrick Watkins
- School of Chemistry, The University of Melbourne, Victoria 3010, Australia
| | - Eduardo Carrascosa
- School of Chemistry, The University of Melbourne, Victoria 3010, Australia
| | - James N Bull
- School of Chemistry, The University of Melbourne, Victoria 3010, Australia
| | - Luke Weston
- School of Chemistry, The University of Melbourne, Victoria 3010, Australia
| | - Giel Muller
- School of Chemistry, The University of Melbourne, Victoria 3010, Australia
| | - Michael S Scholz
- School of Chemistry, The University of Melbourne, Victoria 3010, Australia
| | - Evan J Bieske
- School of Chemistry, The University of Melbourne, Victoria 3010, Australia
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6
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Peeters E, Mackie C, Candian A, Tielens AGGM. A Spectroscopic View on Cosmic PAH Emission. Acc Chem Res 2021; 54:1921-1933. [PMID: 33780617 DOI: 10.1021/acs.accounts.0c00747] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
ConspectusPolycyclic aromatic hydrocarbon molecules (PAHs) are ubiquitously present at high abundances in the Universe. They are detected through their infrared (IR) fluorescence UV pumped by nearby massive stars. Hence, their infrared emission is used to determine the star formation rate in galaxies, one of the key indicators for understanding the evolution of galaxies. Together with fullerenes, PAHs are the largest molecules found in space. They significantly partake in a variety of physical and chemical processes in space, influencing star and planet formation as well as galaxy evolution.Since the IR features from PAHs originate from chemical bonds involving only nearest neighbor atoms, they have only a weak dependence on the size and structure of the molecule, and it is therefore not possible to identify the individual PAH molecules that make up the cosmic PAH family. This strongly hampers the interpretation of their astronomical fingerprints. Despite the lack of identification, constraints can be set on the characteristics of the cosmic PAH family thanks to a joint effort of astronomers, physicists, and chemists.This Account presents the spectroscopic properties of the cosmic PAH emission as well as the intrinsic spectroscopic properties of PAHs and astronomical modeling of the PAH evolution required for the interpretation of the cosmic PAH characteristics. We discuss the observed spectral signatures tracing PAH properties such as charge, size, and structure and highlight the related challenges. We discuss the recent success of anharmonic calculations of PAH infrared absorption and emission spectra and outline the path forward. Finally, we illustrate the importance of models on PAH processing for the interpretation of the astronomical data in terms of the charge balance and PAH destruction.Throughout this Account, we emphasize that huge progress is on the horizon on the astronomical front. Indeed, the world is eagerly awaiting the launch of the James Webb Space Telescope (JWST). With its incredible improvement in spatial resolution, combined with its complete spectral coverage of the PAH infrared emission bands at medium spectral resolution and superb sensitivity, the JWST will revolutionize PAH research. Previous observations could only present spectra averaged over regions with vastly different properties, thus greatly confusing their interpretation. The amazing spatial resolution of JWST will disentangle these different regions. This will allow us to quantify precisely how PAHs are modified by the physical conditions of their host environment and thus trace how PAHs evolve across space. However, this will only be achieved when the necessary (and still missing) fundamental properties of PAHs, outlined in this Account, are known. We strongly encourage you to join this effort.
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Affiliation(s)
- Els Peeters
- Department of Physics & Astronomy, University of Western Ontario, London, Ontario, Canada
- Institute for Earth and Space Exploration, University of Western Ontario, London, Ontario, Canada
- SETI Institute, 189 Bernardo Avenue, Suite 100, Mountain View, California 94043, United States
| | - Cameron Mackie
- Lawrence Berkeley National Laboratory, University of California, Berkeley, California 94720, United States
| | - Alessandra Candian
- van’t Hoff Institute for Molecular Sciences, University of Amsterdam, Amsterdam, The Netherlands
- Leiden Observatory, Leiden University, Leiden, The Netherlands
| | - Alexander G. G. M. Tielens
- Leiden Observatory, Leiden University, Leiden, The Netherlands
- University of Maryland, College Park, Maryland 20742, United States
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7
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Wiersma SD, Candian A, Bakker JM, Berden G, Eyler JR, Oomens J, Tielens AGGM, Petrignani A. IR photofragmentation of the phenyl cation: spectroscopy and fragmentation pathways. Phys Chem Chem Phys 2021; 23:4334-4343. [DOI: 10.1039/d0cp05554a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We present the gas-phase infrared spectra of the phenyl cation, phenylium, in its perprotio (C6H5+) and perdeutero (C6D5+) forms, in the 260–1925 cm−1 (5.2–38 μm) spectral range, and investigate the observed photofragmentation.
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Affiliation(s)
- Sandra D. Wiersma
- Van’t Hoff Institute for Molecular Sciences
- University of Amsterdam
- Amsterdam
- The Netherlands
- Radboud University
| | - Alessandra Candian
- Van’t Hoff Institute for Molecular Sciences
- University of Amsterdam
- Amsterdam
- The Netherlands
| | - Joost M. Bakker
- Radboud University
- Institute for Molecules and Materials
- FELIX Laboratory
- 6525 ED Nijmegen
- The Netherlands
| | - Giel Berden
- Radboud University
- Institute for Molecules and Materials
- FELIX Laboratory
- 6525 ED Nijmegen
- The Netherlands
| | - John R. Eyler
- Department of Chemistry
- University of Florida
- Gainesville
- USA
| | - Jos Oomens
- Radboud University
- Institute for Molecules and Materials
- FELIX Laboratory
- 6525 ED Nijmegen
- The Netherlands
| | | | - Annemieke Petrignani
- Van’t Hoff Institute for Molecular Sciences
- University of Amsterdam
- Amsterdam
- The Netherlands
- Leiden Observatory
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8
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Murga MS, Wiebe DS, Vasyunin AI, Varakin VN, Stolyarov AV. Experimental and theoretical studies of photoinduced reactions in the solid phase of the interstellar medium. RUSSIAN CHEMICAL REVIEWS 2020. [DOI: 10.1070/rcr4912] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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9
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Laboratory Photochemistry of Covalently Bonded Fluorene Clusters: Observation of an Interesting PAH Bowl-forming Mechanism. ACTA ACUST UNITED AC 2019. [DOI: 10.3847/1538-4357/aafe10] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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10
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Jusko P, Brünken S, Asvany O, Thorwirth S, Stoffels A, van der Meer L, Berden G, Redlich B, Oomens J, Schlemmer S. The FELion cryogenic ion trap beam line at the FELIX free-electron laser laboratory: infrared signatures of primary alcohol cations. Faraday Discuss 2019; 217:172-202. [DOI: 10.1039/c8fd00225h] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The FELion beamline – a cryogenic 22-pole trap for vibrational spectroscopy of molecular ions at the FELIX Laboratory.
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Affiliation(s)
- Pavol Jusko
- I. Physikalisches Institut
- Universität zu Köln
- 50937 Köln
- Germany
| | - Sandra Brünken
- I. Physikalisches Institut
- Universität zu Köln
- 50937 Köln
- Germany
- Radboud University
| | - Oskar Asvany
- I. Physikalisches Institut
- Universität zu Köln
- 50937 Köln
- Germany
| | - Sven Thorwirth
- I. Physikalisches Institut
- Universität zu Köln
- 50937 Köln
- Germany
| | - Alexander Stoffels
- I. Physikalisches Institut
- Universität zu Köln
- 50937 Köln
- Germany
- Radboud University
| | - Lex van der Meer
- Radboud University
- Institute for Molecules and Materials
- FELIX Laboratory
- 6525 ED Nijmegen
- The Netherlands
| | - Giel Berden
- Radboud University
- Institute for Molecules and Materials
- FELIX Laboratory
- 6525 ED Nijmegen
- The Netherlands
| | - Britta Redlich
- Radboud University
- Institute for Molecules and Materials
- FELIX Laboratory
- 6525 ED Nijmegen
- The Netherlands
| | - Jos Oomens
- Radboud University
- Institute for Molecules and Materials
- FELIX Laboratory
- 6525 ED Nijmegen
- The Netherlands
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11
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Noble JA, Aupetit C, Descamps D, Petit S, Simon A, Mascetti J, Ben Amor N, Blanchet V. Ultrafast electronic relaxations from the S3 state of pyrene. Phys Chem Chem Phys 2019; 21:14111-14125. [DOI: 10.1039/c8cp06895j] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The ultrafast relaxation occurring in pyrene upon excitation at 4.68 eV was studied in a supersonic gas-jet fs pump–probe experiment.
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Affiliation(s)
| | | | | | - Stéphane Petit
- Université de Bordeaux-CNRS-CEA, CELIA, UMR5107
- F33405 Talence
- France
| | - Aude Simon
- Université de Toulouse-CNRS-UT3, LCPQ-IRSAMC
- F-31062 Toulouse
- France
| | | | - Nadia Ben Amor
- Université de Toulouse-CNRS-UT3, LCPQ-IRSAMC
- F-31062 Toulouse
- France
| | - Valérie Blanchet
- Université de Bordeaux-CNRS-CEA, CELIA, UMR5107
- F33405 Talence
- France
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12
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Chen T, Zhen J, Wang Y, Linnartz H, Tielens AG. From planes to bowls: Photodissociation of the bisanthenequinone cation. Chem Phys Lett 2018. [DOI: 10.1016/j.cplett.2017.12.043] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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13
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Laboratory spectroscopy and astronomical significance of the fully-benzenoid PAH triphenylene and its cation. ACTA ACUST UNITED AC 2017. [DOI: 10.1016/j.molap.2017.04.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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14
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15
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de Haas AJ, Oomens J, Bouwman J. Facile pentagon formation in the dissociation of polyaromatics. Phys Chem Chem Phys 2017; 19:2974-2980. [DOI: 10.1039/c6cp08349h] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Energetic processing of gaseous polycyclic aromatic hydrocarbons (PAHs) plays a pivotal role in the chemistries of inter- and circumstellar environments, certain planetary atmospheres, and also in the chemistry of combustion and soot formation.
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Affiliation(s)
- Arjen J. de Haas
- Radboud University
- Institute for Molecules and Materials
- FELIX Laboratory
- 6525ED Nijmegen
- The Netherlands
| | - Jos Oomens
- Radboud University
- Institute for Molecules and Materials
- FELIX Laboratory
- 6525ED Nijmegen
- The Netherlands
| | - Jordy Bouwman
- Radboud University
- Institute for Molecules and Materials
- FELIX Laboratory
- 6525ED Nijmegen
- The Netherlands
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16
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Zhen J, Castellanos P, Paardekooper DM, Ligterink N, Linnartz H, Nahon L, Joblin C, Tielens AGGM. LABORATORY PHOTO-CHEMISTRY OF PAHS: IONIZATION VERSUS FRAGMENTATION. THE ASTROPHYSICAL JOURNAL. LETTERS 2015; 804:L7. [PMID: 26688710 PMCID: PMC4681094 DOI: 10.1088/2041-8205/804/1/l7] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Interstellar Polycyclic Aromatic Hydrocarbons (PAH) are expected to be strongly processed by Vacuum Ultra-Violet (VUV) photons. Here, we report experimental studies on the ionization and fragmentation of coronene (C24H12), ovalene (C32H14) and hexa-peri-hexabenzocoronene (HBC; C42H18) cations by exposure to synchrotron radiation in the range of 8-40 eV. The results show that for small PAH cations such as coronene, fragmentation (H-loss) is more important than ionization. However, as the size increases, ionization becomes more and more important and for the HBC cation, ionization dominates. These results are discussed and it is concluded that, for large PAHs, fragmentation only becomes important when the photon energy has reached the highest ionization potential accessible. This implies that PAHs are even more photo-stable than previously thought. The implications of this experimental study for the photo-chemical evolution of PAHs in the interstellar medium (ISM) are briefly discussed.
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Affiliation(s)
- Junfeng Zhen
- Leiden Observatory, University of Leiden, P.O. Box 9513, 2300 RA Leiden, The Netherlands ; Sackler Laboratory for Astrophysics, Leiden Observatory, University of Leiden, P.O. Box 9513, 2300 RA Leiden, The Netherlands ; Universitè de Toulouse, UPS-OMP, IRAP, Toulouse, France ; CNRS, IRAP, 9 Av. colonel Roche, BP 44346, 31028, Toulouse Cedex 4, France
| | - Pablo Castellanos
- Leiden Observatory, University of Leiden, P.O. Box 9513, 2300 RA Leiden, The Netherlands ; Sackler Laboratory for Astrophysics, Leiden Observatory, University of Leiden, P.O. Box 9513, 2300 RA Leiden, The Netherlands
| | - Daniel M Paardekooper
- Sackler Laboratory for Astrophysics, Leiden Observatory, University of Leiden, P.O. Box 9513, 2300 RA Leiden, The Netherlands
| | - Niels Ligterink
- Leiden Observatory, University of Leiden, P.O. Box 9513, 2300 RA Leiden, The Netherlands ; Sackler Laboratory for Astrophysics, Leiden Observatory, University of Leiden, P.O. Box 9513, 2300 RA Leiden, The Netherlands
| | - Harold Linnartz
- Sackler Laboratory for Astrophysics, Leiden Observatory, University of Leiden, P.O. Box 9513, 2300 RA Leiden, The Netherlands
| | - Laurent Nahon
- Synchrotron SOLEIL, L'Orme des Merisiers, 91192 Gif sur Yvette Cedex, France
| | - Christine Joblin
- Universitè de Toulouse, UPS-OMP, IRAP, Toulouse, France ; CNRS, IRAP, 9 Av. colonel Roche, BP 44346, 31028, Toulouse Cedex 4, France
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17
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Zhen J, Castellanos P, Paardekooper DM, Linnartz H, Tielens AGGM. LABORATORY FORMATION OF FULLERENES FROM PAHS: TOP-DOWN INTERSTELLAR CHEMISTRY. ACTA ACUST UNITED AC 2014. [DOI: 10.1088/2041-8205/797/2/l30] [Citation(s) in RCA: 130] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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18
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West B, Sit A, Mohamed S, Joblin C, Blanchet V, Bodi A, Mayer PM. Dissociation of the anthracene radical cation: a comparative look at iPEPICO and collision-induced dissociation mass spectrometry results. J Phys Chem A 2014; 118:9870-8. [PMID: 25245634 DOI: 10.1021/jp505438f] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The dissociation of the anthracene radical cation has been studied using two different methods: imaging photoelectron photoion coincidence spectrometry (iPEPCO) and atmospheric pressure chemical ionization-collision induced dissociation mass spectrometry (APCI-CID). Four reactions were investigated: (R1) C14H10(+•) → C14H9(+) + H, (R2) C14H9(+) → C14H8(+•) + H, (R3) C14H10(+•) → C12H8(+•) + C2H2 and (R4) C14H10(+•) → C10H8(+•) + C4H2. An attempt was made to assign structures to each fragment ion, and although there is still room for debate whether for the C12H8(+•) fragment ion is a cyclobuta[b]naphthalene or a biphenylene cation, our modeling results and calculations appear to suggest the more likely structure is cyclobuta[b]naphthalene. The results from the iPEPICO fitting of the dissociation of ionized anthracene are E0 = 4.28 ± 0.30 eV (R1), 2.71 ± 0.20 eV (R2), and 4.20 ± 0.30 eV (average of reaction R3) whereas the Δ(‡)S values (in J K(-1) mol(-1)) are 12 ± 15 (R1), 0 ± 15 (R2), and either 7 ± 10 (using cyclobuta[b]naphthalene ion fragment in reaction R3) or 22 ± 10 (using the biphenylene ion fragment in reaction R3). Modeling of the APCI-CID breakdown diagrams required an estimate of the postcollision internal energy distribution, which was arbitrarily assumed to correspond to a Boltzmann distribution in this study. One goal of this work was to determine if this assumption yields satisfactory energetics in agreement with the more constrained and theoretically vetted iPEPICO results. In the end, it did, with the APCI-CID results being similar.
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Affiliation(s)
- Brandi West
- Chemistry Department, University of Ottawa , Ottawa, Canada K1N 6N5
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